Maybe when Jupyter Notebook's release v7 is out, which is based on jupyterlab, it makes sense to switch the default renderer to one that support offline rendering? This is not the highest priority right now, but I thought I would record the idea. Maybe we could also trim down the amount of available renderers to simplify the selection a bit (at least html and default are the same, maybe also jupyterlab and mimetype?). Based on the discussion here vega/vegafusion#204 (reply in thread)